Continuation for final year of budgeted support for research project involving the effects of gastrointestinal hormones on growth of mucosa of stomach, small and large intestine. The upcoming studies will assess the roles of glucagon, vagal stimulation, and vasoactive intestinal peptide in growth of gastric and colonic mucosa. Most studies will involve measurement of DNA synthesis in the rat. We will also test whether or not cAMP plays a role in mediating the response to gastrin. The involvement of other endocrine substances such as cortisone and thyroxine will be examined in adrenolectomized, hypophysectomized and thyroidectomized animals. BIBLIOGRAPHIC REFERENCES: L.R. Johnson and P.D. Guthrie.: Effect of cholecystokinin and 16,16-dimethyl prostaglandin E2 on RNA and DNA of gastric and duodenal mucosa. Gastroenterology 70: 278-288, February, 1976. L. Lichtenberger, J.D. Welsh and L.R. Johnson.: Relationship between the changes in gastrin levels and intestinal properties in the starved rat. Amer. J. Dig. Dis. 21:33-38, January 1976.